title: MicroRNA profiling in ocular adnexal lymphoma: a role for MYC and NFKB1 mediated dysregulation of microRNA expression in aggressive disease.
abstract: OBJECTIVE
  Ocular adnexal lymphoma (i.e., lymphoma with involvement of the orbit, eyelids, conjunctiva, lacrimal gland, and lacrimal sac), although rare, is common among malignant tumors involving the ocular adnexal region. The main subtypes are low-grade extranodal marginal zone lymphoma (EMZL) and aggressive diffuse large B-cell lymphoma (DLBCL). In rare cases, low-grade EMZL are reported to transform to DLBCL. It is unclear, however, which genetic events distinguish low-grade disease from aggressive, potentially fatal disease.
  
  
  METHODS
  Using LNA-based arrays from Exiqon, we performed global microRNA (miRNA) expression profiling of 18 EMZLs and 25 DLBCLs involving ocular adnexal sites to investigate changes in the miRNA expression in low- versus high-grade disease. Findings were confirmed by real-time quantitative PCR (RTq-PCR).
  
  
  RESULTS
  Our analysis revealed 43 miRNAs with altered expression profiles in DLBCL compared to EMZL. Seven of the miRNAs down-regulated in DLBCL relative to EMZL showed enrichment for a direct transcriptional repression by the oncoprotein MYC. We also report a possible loss-of-regulation of NFKB1 and its downstream miRNAs. In addition, our analysis identified a group of DLBCLs whose expression profiles resembled that of EMZL. Although transformation of EMZL to DLBCL in the ocular adnexal region is rare, we hypothesize that the intermediate group potentially may derive from transformation of EMZL that was not recognized by histology.
  
  
  CONCLUSIONS
  We conclude that fundamental differences in miRNA expression exist between ocular adnexal EMZL and DLBCL, mainly due to differences in MYC and NF-ĸB regulatory pathways.
authors.affiliation: Department of Hematology, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Christoffer
authors.initials: C
authors.lastname: Hother
authors.forename: Peter Kristian
authors.initials: PK
authors.lastname: Rasmussen
authors.forename: Tejal
authors.initials: T
authors.lastname: Joshi
authors.forename: Ditte
authors.initials: D
authors.lastname: Reker
authors.forename: Ulrik
authors.initials: U
authors.lastname: Ralfkiær
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Workman
authors.forename: Steffen
authors.initials: S
authors.lastname: Heegaard
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Ralfkiær
authors.forename: Kirsten
authors.initials: K
authors.lastname: Grønbæk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003230:Conjunctival Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005134:Eye Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007765:Lacrimal Apparatus / Q000378:metabolism / Q000473:pathology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008297:Male; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics*; D008875:Middle Aged; D052002:NF-kappa B p50 Subunit / Q000096:biosynthesis / Q000235:genetics*; D009918:Orbital Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D040081:Protein Array Analysis / Q000379:methods; D016271:Proto-Oncogene Proteins c-myc / Q000096:biosynthesis / Q000235:genetics*; D012334:RNA, Neoplasm / Q000096:biosynthesis / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: C489427:MYC protein, human; D035683:MicroRNAs; D052002:NF-kappa B p50 Subunit; C489548:NFKB1 protein, human; D016271:Proto-Oncogene Proteins c-myc; D012334:RNA, Neoplasm
keywords: DLBCL; EZML; microRNA; ocular adnexal lymphoma